000
AXPZ20 KNHC 010909
TWDEP 

TROPICAL WEATHER DISCUSSION  
NWS NATIONAL HURRICANE CENTER MIAMI FL
1005 UTC TUE MAR 01 2011

TROPICAL WEATHER DISCUSSION FOR THE EASTERN PACIFIC OCEAN FROM 
THE EQUATOR TO 32N...EAST OF 140W.

BASED ON 0600 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH 
0730 UTC.

...ITCZ...

THE INTERTROPICAL CONVERGENCE ZONE AXIS IS ANALYZED FROM 06N77W 
TO 02N95W TO 05N125W TO 03N134W TO 04N140W. SCATTERED MODERATE 
WITH ISOLATED STRONG CONVECTION LIES WITHIN 180 NM N OF THE ITCZ 
AXIS BETWEEN 79W AND 86W WHILE SCATTERED MODERATE CONVECTION IS 
WITHIN 240 NM N OF THE ITCZ AXIS BETWEEN 120W AND 131W.
 
...DISCUSSION...

AN EXPANSIVE ANTICYCLONE ALOFT CENTERED NEAR 16N90W IS 
ASSOCIATED WITH AN AREA OF SUBSIDENCE AND DRY AIR IN THE MID TO 
UPPER LEVELS OVER MUCH OF THE AREA BETWEEN 10N AND 25N E OF 
115W. BROAD DIFFLUENT FLOW ALOFT BETWEEN THIS ANTICYCLONE AND AN 
UPPER LOW S OF THE EQUATOR NEAR 15S90W IS ENHANCING VERTICAL 
MOTION NEAR THE ITCZ E OF 90W. CONVECTION THERE IS DESCRIBED IN 
THE ITCZ SECTION ABOVE.

ANOTHER DEEP LAYER TROUGH IS OVER NW WATERS. ITS UPPER TROUGH 
AXIS LIES FROM 32N129W THROUGH 17N132W TO 02N160W WHILE A MUCH 
WEAKER NEGATIVELY TILTED UPPER TROUGH LIES FROM 10N125W TO 
05N110W. A BROAD AREA OF 50-70 KT SW WINDS LIES BETWEEN THESE 
TWO TROUGHS AND IS TRANSPORTING MID TO UPPER LEVEL MOSITURE FROM 
THE TROPICS INTO N WATERS WITH MULTIPLE CLOUD LAYERS NOTED OVER 
MUCH OF THE AREA N OF 10N AND W OF 120W. THE ATTENDANT COLD 
FRONT IS MOVING INTO THE FORECAST AREA AND LIES FROM A 1006 MB 
LOW PRES SYSTEM NEAR 30N140W THROUGH 28N140 TO THE ALENUIHAHA 
CHANNEL IN THE HAWAIIAN ISLANDS. THE 0638Z ASCAT PASS AND SHIP 
GBQV SHOW STRONG SOUTHERLY WINDS AHEAD OF THE FRONT TO 130W. THE 
FRONT WILL SLOWLY MOVE SOUTHEASTWARD THROUGH WED MORNING WITH 
FRESH TO STRONG WINDS REMAINING AHEAD OF THE FRONT OVER N WATERS 
BETWEEN IT AND HIGH PRES TO ITS E. THE FRONT WILL DISSIPATE AND 
WINDS WILL DIMINISH BELOW ADVISORY CRITERIA BY THU MORNING.

BROAD SURFACE RIDGING CURRENTLY DOMINATES PACIFIC FORECAST 
WATERS N OF 15N AND E OF 130W. THE PRES GRADIENT BETWEEN THIS 
RIDGING AND LOWER PRES ASSOCIATED WITH THE ITCZ IS PRODUCING AN 
AREA OF FRESH TRADE WINDS PRIMARILY FROM 07N TO 19N BETWEEN 120W 
AND 135W. THESE TRADES WILL MIGRATE SOUTHWESTWARD AS THE HIGH 
PRES CENTER TO THE N IS FORCED SOUTHWARD BY THE APPROACHING COLD 
FRONT AND RIDGING AMPLIFIES SOUTHWESTWARD AHEAD OF THE FRONT. 

GULF OF CALIFORNIA...HIGH PRES IS BUILDING BOTH ON THE E SIDE OF 
THE GULF OF CALIFORNIA BEHIND A COLD FRONT CURRENTLY OVER THE 
CENTRAL GULF OF MEXICO AS WELL ON THE W SIDE WHERE THE PACIFIC 
HIGH IS BEING FORCED EASTWARD BY THE APPROACHING COLD FRONT IN 
NW WATERS. THE 0456Z ASCAT PASS AND SHIP 3FPR9 CONFIRM FRESH TO 
STRONG NW WINDS IN THE GULF OF CALIFORNIA S OF 28N. THE PRES 
GRADIENT WILL WEAKEN SLIGHTLY BY WED MORNING...BUT WINDS WILL 
REMAIN NEAR 20 KT HERE THROUGH THE FORECAST PERIOD. OVERNIGHT 
WED NIGHT...NW WINDS WILL INCREASE TO 20 KT ON THE WESTERN SIDE 
OF THE BAJA PENINSULA AS THE MEAN SURFACE RIDGE...ALONG WITH THE 
STRONGEST PRES GRADIENT...SHIFTS W. 

GULF OF TEHUANTEPEC...THE COLD FRONT SWEEPING SE ACROSS THE 
CENTRAL GULF OF MEXICO HAS SENT POST FRONTAL NORTHERLY WINDS AT 
15 TO 20 KT INTO THE GULF OF TEHUANTEPEC THIS MORNING. WINDS 
HERE ARE EXPECTED TO INCREASE TO GALE FORCE JUST AFTER SUNRISE 
THIS MORNING. GALE CONDITIONS WILL CONTINUE UNTIL JUST AFTER 
SUNRISE WED MORNING...WITH WINDS DIMINISHING TO 20 KT BY THU 
MORNING. 

GULF OF PAPAGAYO...NE TO E WINDS WILL CONTINUE TO PULSE AT 15 TO 
20 KT TODAY THEN INCREASE TO 20 TO 25 KT BY WED MORNING AS HIGH 
PRES BUILDS S OVER CENTRAL AMERICA BEHIND THE AFOREMENTIONED 
COLD FRONT.

GULF OF PANAMA...N WINDS TO 20 KT ARE EXPECTED OVERNIGHT WED 
NIGHT AS HIGH PRES BUILDS S THROUGH CENTRAL AMERICA...INCREASING 
THE PRES GRADIENT BETWEEN IT AND LOW PRES OVER COLOMBIA.

$$
SCHAUER